Dryer ventilating roll



R. A. DAANE DRYER VENTILATING ROLL ocr. 1o, 1967 3 Sheets-Sheetl- Filedoct. 14, 1965 INVENTOR. Eojef. Dwaze@ @M i 9 l ATTORNEYS Oct. 10, 1967R. A. DAANE' DRYER VENTI'LATING ROLL 5 Sheets-Sheet 2 Filed Oct. 14,1965 hkm. MN wk D. Q nv W@ DE Q WWW IN VENTOR. Eobe. afazze @Ld-u' Q YEN lay

W ATTORNEYS ot.1o,1967 RADAANE I 3,345,757.

DRYER VENT ILATING ROLL Filed Oct. 14, 1965 3 Sheets-Sheet 3 I N VENTOR.

/sywiw ATTORNEYS United States Patent 3,345,757 DRYER VENTILATING RGLLRobert A. Daane, Rockford, Ill., assigner to Beloit Corporation, Beloit,Wis., a corporation of Wisconsin Filed 0er. 14, 1965, Ser. No. 495,859 7Claims. (Cl. .M -111) i ABSTRACT 0F THE DISCLGSURE Ventilating feltroller, Ventilating and purging the felt pocket of a web dryer fromvapor. The felt roller has a perforate periphery with a central airdistributing shell spaced inwardly of the periphery of the roller andsealed to the interior of the roller to direct air through the perforateperiphery of the roller into the yfelt pocket. The flow of air throughthe distributor shell may be varied at each end portion of the shellthrough independently yadjustable air modulating valves at opposite endsof the distributor shell.

This invention relates to improvements in felt dryers for the dryingline of a paper machine and more par-ticularly relates to an improvedform of pocket Ventilating feltV roller.

A principal object of the present invention is to provide an improvedform of Ventilating felt roller arranged with a view toward moreuniformly drying and conditioning of the felt as it passes from one4drying cylinder to another.

A further object of the invention is to provide a ventilating system forthe felt pockets of web dryers, uniformly purging the felt pockets fromvapor, and thereby increasing the rate of drying of the web as the webpasses from the outgoing side of one drying cylinder to the incomingsideA of a next adjacent drying cylinder.

A still further object of the invention is to increase the rate ofdrying of paper webs and the like by passing heated air through the feltand transferring the heat of the feit to the web as the felt passes overthe web on the dryer.

A still kfurther object of the invention is to provide an improvedsystem for leveling the moist-ure prole of paper machine dryers bypassing heated air through the felt, into the felt pockets and to sodistribute the air as to uniformly dry the web 'throughout the widththereof.

A still further object of the invention is to improveupon the drying ofpaper webs and the like in the drying section of a paper machine, bypassing a sufficient quantity of heated air through the felt roller intothe 'felt pocket to purge the air from the pocket from where it passesout from both ends of the pocket.

A still further object of the invention is to provide a simple andimproved form of telt roller, reducing and leveling felt pocket vaporpressure while heating and drying the felt, and thereby increasing thedrying capacity of the dryer and flattening the sheet moisture proiile.

Still another object of the invention is to provide an improved form ofVentilating dryer roller in which the periphery of the roller hasuniformly spaced indentations extending longitudinally therealong withair flow orifices opening into the indentations, to thereby support thefelt free `from the discharge ends of the air ow orifices and to providea more ellcient and increased air ow area through the felt.

A still further object of the invention is to provide an innerstationary air distributing shell -for distributing air to iiow throughthe perforated periphery of a .felt roller having an air ow lpattern ofdecreasing density-toward the far end of the distributor, to compensatefor high 3,345,752 Patented Oct. 10, 1967 velocity pressure and lowstatic pressure at the inlet end of the roll and to thereby uniformlydistribute the air along the periphery of the felt roll into the feltpocket.

These and other objects of the invention will appear from time to timeas the following specication proceeds and with reference to theaccompanying drawings where- 1n:

FIGURE l is a diagrammatic view of a part of a typical dry end sectionof a paper machine, incorporating a felt pocket Ventil-ating systemconstructed in accordance with the principles of the present invention;

FIGURE 2 is 4a longitudinal sectional view taken through one-half of amodulated `felt roller constructed in accordance with the principles ofthe present invention;

FIGURE 3 is a longitudinal continuation of the modulated Ventilatingfelt roll illustrated in FIGURE 2;

FIGURE 4 is a transverse sectional view taken substantially along lineIV--IV of FIGURE 3;

FIGURE 5 is an enlarged fragmentary detail sectional view, illustratingcertain details of the longitudinal sealing arrangement between thedistributor shell and the inner periphery of the felt roll;

FIGURE -6 is a diagrammatic view illustrating a pattern of the peripheryof the distributor shell not having modulating valves `at opposite endsof the shell; and

FIGURE 7 is a transverse sectional View of a moditied form of feltroller constructed in accordance with the principles of the presentinvention.

In the embodiment of the invention illustrated in the drawings, I haveshown in FIGURE 1, a paper machine dry end section 10 and including anupper tier of drying cylinders 11 arranged in a row, and a lower tier ofdry- -ing cylinders 12 vertically staggered with respect to the uppertier of drying cylinders 11. The dryinD cylinders 11 and 12 have a web Wtrained thereabout in a serpentine path throughout the length of thedryer section.

The web is partially wrapped about a first and second of the top tier ofdrying cylinders by a Kfelt 13, maintaining the web in close contactwith its drying cylinders and partially wrapped to the web, passingabout the drying cylinders, by felt rollers 15, 15. As shown in FIGURE 1only a part of the tier of upper dryer cylinders is shown r and the feltis trained from the second drying cylinderV 11 from the left, upwardlyabout an idler 16 from which it is trained to a iirst drying cylinder ofa series of drying cylinders. A dryer hood 17 is shown as extendingpartially about the third drying cylinder from the lett of the uppertier of drying cylinders, for impinging heated air on the web prior topassing beyond the end of the dryer. The dryer hood, however, forms nopart of the present invention and need not necessarily be in the uppertier of drying cylinders.

The web is partially wrapped around the bottom series of dryingcylinders 12, 12 by a felt 18, partially wrapped about said cylinders byfelt rollers 19, 19 between the drying cylinders and end felt rollers 20and 21. The felt passes from the end felt roller 21 around spaced idlers22, 22 turning the felt from the telt roller 21 beneath the dryingcylinders 12, 12 to and around the felt roller 20, to an incoming dryingcylinder 12.

The felt roller 15 between two dryer drums 11, 11 trains the felt topass out of contact with the web from the outgoing side of one dryingcylinder 11 to the incoming side of the next adjacent drying cylinder11. The felt being out of contact with the web, moisture in the web isevaporated and proceeds outwardly of the web and collects in a pocketbetween the outgoing side .of one drying cylinder 11 and the incomingside of the next adjacent drying cylinder 11 as well as the nextdownwardly spaced cylinder 12. This pocket is indicated by referencecharacter 25 and is commonly termed a felt pocket, Additional pocketsare formed between each outgoing and incoming dryer cylinder 11, 11 and12, 12 for the length of the dryer line.

Moisture in the pockets inhibits evaporation from the web, requiring anincreased dryer and web temperature and also increasing the drying time.

It should here be understood that the felts 13 and 18 are formed from aporous material and may be of any type fabric which will allow air to bepassed through it. The felts also may be formed of plastic wire fabricsuch as used on fourdriniers, a suitable material being a foraininousplastic wire or fabric of the type known as Formex fabric, which permitsmoisture vapor to be driven through the fabric and out of the ends ofthe fabric, by heated air passing out through the periphery of a feltroller.

The upper felt rollers 15 and the lower felt rollers 19 are of similarconstructions so the upper felt rollers 15 only need herein be shown anddescribed.

As shown in FIGURES 2, 3, 4 and 5, the felt roller 15 includes arotatable cylindrical perforate outer shell and a stationary cylindricalinner air distribution shell 26, spaced radially inwardly of the innerperiphery of the outer shell and extending for substantially the lengthof said outer shell and coaxial therewith.

The outer shell 25 has rings 27 and 28 bolted to the ends thereof andforming continuations of the periphery thereof to retain the felt fromexposure to any non-rotating surfaces at each end of the shell and toshroud Stationary oil collectors 29 and 30 respectively.

The ring 27 abuts the end of the shell 25 and extends inwardlytherealong for a portion of the length thereof and has a plate 31secured to its inner end and cooperating with a stationary hollowsupport shaft 32 to act as an oil collector to prevent oil from mixingwith air within the shell 25. The ring 27 forms a mounting for a bearingsupport 33 rotatably supporting the front end :of the shell 25 on astationary hollow shaft 32 on suitable bearings, herein shown as beingthrust types of roller bearings 36.

The ring 28 abuts the outer side of a radially flanged bearing support37, supporting the back end of the shell 25 on a stationary air inletmember 39 having a ared discharge throat 40 to produce a venturi effectas heated air is supplied to the interior of the shell 26. The outer endof the air inlet member 39 extends within an air supply pipe 41 and maybe slidingly fitted thereto. The air supply pipe 41 is connected with asource of supply of heated air and may be supported on the dryer framein a suitable manner and form a support for one end of the airdistributing shell 26. The air may preferably be hot dry air of atemperature `of 250 F. with a maximum moisture content of 300 grams ofwater per pound of dry air at the distributor entrance.

The outer shell or roll 25 may be formed from a mild steel centrifugalcasting, turned and bored and then grooved with a plurality oflongitudinal extending grooves 43 extending for the length thereof andequally spaced thereabout. Air distributing passageways or orifices 44may then be drilled through the grooved portions of the shell at equallyspaced intervals along the grooved portions thereof. The drillingpattern is herein shown as being a uniform rectangular drilling pattern.The diameters of the passageways 44 and drilling pattern thereof is suchas to give a minimum of 5% open area. Such a drilling pattern results ina very stiif roll of a deflection less than the conventional felt roll,the roll would replace. In order to increase the open area at theinterface between the roll and the felt without weakening the rotatingshell, the longitudinal grooves have been machined along the peripheryof the shell. The groovesI are relatively shallow and are ared at eachside and make it possible to have an interface open area such that 80%of the felt is directly exposed to the air coming through the passageway44.

The air distributing shell 26 is shown as abutting annular ring seats 45at its opposite ends, which may be welded or otherwise secured to theend of the shell. The ring seat 45 at one end of the distributor shell26 extends about a hollow drum 46, shown as being formed integrally withthe stationary shaft 32. The ring seat abuts a radial flange 47extending radially of said drum. Machine screws 48 are provided tosecure the ring seat 45 4and shell 26 to the drum 46. The drum 46extends inwardly along the shell, for a short portion of the lengththereof, and -opens toward the interior of the shell and serves as anend frame member for the shell to retain air from passing through theend thereof.

The opposite ring seat 45 extends along the periphery of the air inletmember 4t) and abuts a radially extending flange 49 of said air member,and is secured thereto as by machine screws 50. The annular ring seats45, 45 have ring grooves 51 formed therein for receiving sealing rings53, which may be cast iron piston rings, expanding out against the innersurface of the outer shell and rotating with said outer shell.Alternatively, the piston rings may be of a non-metallic material suchas that known by the trade name Pyrotex Ring seats 55 similar to thering seats 45 encircle the shell 26 in inwardly spaced relation withrespect to the ring seats 45 at the inner end portions of modulatorvalves l56, 56 at opposite ends of the shell. The ring seats 55 may -bewelded or otherwise secured to the periphery of the shell 26 and carrypiston rings 57 like the piston rings 53, expanding out against theinner surface of the shell 25 and rotating therewith.

The air distributing shell 26 has an imperforate wall portion 59 on theopposite side of the shell from the felt and has a perforate wallportion 60 having a plurality of air ow passageways or orices 61, 61leading therethrough.

Where the felt roller 15 is a non-modulating type of roller, thedrilling pattern may be graduated as diagrammatically shown in FIGURE 6,to decrease the density of the holes toward the closed ends of the airdistributing shell. This design relies on the fact that the totalpressure is the sum of the static pressure and the velocity pressure,and at the inlet, where the velocity pressure is at a maximum, thestatic pressure is low. As the closed end of the shell is approached thevelocity decreases7 thus lowering the velocity pressure, while thestatic pressure increases, requiring less open area for the same rate offlow per foot of felt, to compensate for the reduced static pressure onthe ends of the air distributor shell, because of the high velocity ofthe air, and to thereby provide a uniform discharge of air across theroll width.

Where, however, the shell has modulator valves therein, such as themodulator valves 56 shown in FIGURES 2, 3 and 4, the hole pattern may beuniform for the length of the roll.

The shell 26 has two longitudinally extending seals 63 extendingradially fr0-m the outer periphery thereof at opposite ends oftheimperforate face 59 of the shell. These longitudinal seals each includea resilient pad 64 extending along the periphery of the shell, and agenerally U-shaped non-metallic seal 65 extending along the top of thepad 64 and having parallel spaced legs 66, 66 engaging the innerperiphery of the outer shell 25. Spaced machine screws 67 extendingthrough collars 69 extending through the base of the seal 65 and therubber pad 64, are provided to retain the seal in position on the shell.The ends of the legs of the seal engage the inner periphery of the outershell during assembly and compress the rubber pad 64, as shown in FIGURE5. The seal is then allowed to run in after assembly and to wear untilthe play in the bolts or machine screws 67 is taken up, as shown in FIG-URE 5.

Alternatively, the longitudinally extending seals may be mounted onhinges and lightly loaded with springs so that they bear against therotating shell with a small but deiinite pressure.

A suitable material from which the non-metallic seals may be made isknown by the trade name of Pyrotex. This material has a low coeiicientof friction and can stand rubbing over long periods of time. Anothermaterial that may be used is known 'by the trade name of Teflon Themodulator valves 56 at each end of the air distributor shell 26 areshown in IFIGURES 2, 3 and 4 as being spoked wheels 70, 70 spaced alongthe axis of the roller at each end thereof. The wheels 70 havecylindrical rims 71 having sealing grooves 72 in the peripheriesthereof, having seals 73 carried therein and engaging the innerperiphery of the air distributor shell 26. The wheels 70 are connectedtogether by a shroud 74 welded or otherwise secured to the legs of anglebrackets 75,V secured to the sides of the rims of the wheels on theright angled legs thereof. The other legs of the angle brackets 75 haveresilient seals 76 clamped thereto by clamping plates 77. The anglebrackets 75 are connected between two adjacent wheels and extend in thespace between the two adjacent wheels and the seals 76, mounted thereon,seal the space covered by the shroud 74.

The two wheels at one end of the air distributing shell 26 are mountedon a sleeve 79 extending through the hollow shaft 32 and outwardlybeyond the end thereof. A suitable securing connection may be providedbetween the sleeve and the two wheels to rotate the wheels together andvary the number of the air distribution passageways 61 in communicationwith the passageways 44, 44, upon the turning of a hand lever 80 on theouter end portion of said sleeve. A shaft 81 extends along the sleeve 79from a position disposed outwardly of said sleeve and has a hand lever82 mounted thereon. The shaft 81 extends beyond the modulator valve 56,operated by the sleeve 79, to and through a sleeve 84 extending alongand connected to the hubs of the wheels 70, 70 of the modulator valve56, at the opposite end of the air distributor shell, and is suitablysecured thereto to be turned upon turning movement of a hand lever 82,to vary the number of the air distributor passageways 61 in the spacebetween the wheels 70, 70.

The two modulator valves 56, 56 therefore provide two sealed cylinderhalves in the air distributor shell 26, one being at each end of theshell, to block off or selectively open certain air passageways 61, 61,to thereby vary the supply of air to the face of the roll 15, at theends of said roll. The two valves 57 are independently operated, so theair llow can be blocked off at the front end portion of the roll or theback end portion of the roll or at both end portions of the roll asrequired. The air passageways at each end of the roll may also be fullyopened.

Although only two modulator valves are herein shown, any number ofvalves may be used.

Suitable dampers (not shown) may be provided in the supply line to thepipe 41 to regulate the entire air supply required. Such dampers may bewell known forms of manually operable butterfly dampers, and are no partof the present invention so need not herein be shown or describedfurther.

In FIGURE 7 I have shown a cross section of a modified form ofnon-modulating felt roll and air distributor therefor. In this form ofthe invention the felt roller is in the form of a shell 85 havingparallel grooves 86 extending longitudinally therealong and 'having rowsof air passageways 87 opening therethrough, as in the form of theinvention illustrated in FIGURES 2, 3, 4 and 5. A stationary airdistributor 88 is mounted within the shell 85 and includes a generallyhemi-cylindrical wall portion 89 having lugs 90, 90 extending radiallyoutwardly from each end thereof and having grooves 91 extendingtherealong receiving seals 92, having sealing engagement with the innerface of the roll shell 85. The air distributing member also has acentral diametral spoke 93 extending from the inner side of thehemi-cylindrical wall portion 89 and having a widened free end portion95 having a seal 96 recessed therein and engaging the inner periphery ofthe roll shell.

Air entering the shell from an end thereof, on opposite sides of thediametral spoke 93, will thus be discharged through the air passageways87 in the periphery of the shell and through a felt trained thereaboutto uniformly dry the felt and also to provide an air supply to drive themoisture vapor from the ends of t'he felt pockets. The air distributor88 may be adjusted about the axis of the roll shell to vary thedistribution of air to the felt, and if desired air may be admitted toone side or the other of the spoke 93 to vary the volume of air passingthrough the felt.

It may be seen from the foregoing that a new and improved felt rollerhas been provided supplying heated air through the felt to not onlypurge the felt pockets of moist air but to also uniformly dry andcondition the felt as it passes from the outgoing side of one dryingcylinder to the incoming side of the next adjacent drying cylinder andthat the felt roll of the present invention, not only increases thedrying capacity of the dryer line, but also irnproves the moistureprofile and eliminates the need for separate felt dryers for the felt asit leaves the outgoing drying cylinder of a tier of drying cylinders andpasses to the incoming drying cylinder of the same tier of dryingcylinders.

While I have herein shown and described one form in which the inventionmay be embodied, it may readily be understood that various variationsand modifications in the invention may be attained without departingfrom the spirit and scope of the novel concepts thereof.

I claim as my invention:

1. In a felt roller for paper machine dryers comprising:

a cylindrical roll shell mounted for free rotation about a horizontalaxis and having a plurality of air passageways leading through theperiphery thereof from the hollow interior thereof for passing heatedair therethrough,

a hollow non-rotatably cylindrical air distributor shell spaced radiallyinwardly of the inner periphery of said roll shell and extendingtherealong and having a perforate area having air distributorpassageways leading therethrough for supplying heated air to said airpassageways leading through the periphery of said roll shell,

circumferentially and axially spaced sealing means sealing said area ofthe interior of said roll shell.

and modulator Vvalve means rotatably mounted at each end of saiddistributor shell for adjustable movement about the inner periphery ofsaid distributor shell,

said modulator valve means having circumferentially and axially spacedseals having sealing engagement 'with the interior of said distributorshell and being movable to seal off the opposite end portions of thepassageways leading through said distributor shell and to vary the flowthrough said passageways,

and adjustment means connected with each modulator valve means foradjustably moving said modulator valve meansindependently of each other.

2. The structure of claim 1,

wherein the modulator valve means comprise imperfo- 4rate shrouds sealedby said sealing means to the interior of said distributor shell alongthe ends and opposite sides of said shrouds.

3. In a drying apparatus for fibrous webs,

a rotatable felt roller partially wrapping a felt to a web trained aboutspaced drying cylinders in a serpentine path,

said roller being hollow and having a plurality of air passagewaysleading through the periphery thereof from the hollow interior thereoffor passing heated air through the felt passing thereabout,

a hollow cylindrical air distributor shell spaced radially inwardly ofthe inner periphery of said roller and extending therealong and havingair distributor passageways leading through a portion of the peripherythereof, for supplying heated air to said air passageways of saidroller,

and modulator valves at opposite ends of said shell for varying the flowrate of air through the opposite end portions of said shell,

said modulator valves comprising:

spaced wheels disposed adjacent each end portion of said shell andaccommodating the flow of air through said shell,

and arcuate shrouds disposed between said wheels and positionable toshroud certain air passageways leading through said shell, at theselection ofthe operator of the machine.

4. In a drying apparatus for fibrous webs,

a hollow rotatably mounted felt roller partially wrapping a felt to aweb trained about spaced drying cylinders in a serpentine path,

a plurality of air passageways leading through said roller from theinterior to the exterior thereof, for forcing heated air through thefelt passing thereabout,

a hollow cylindrical air distributing shell spaced radially inwardly ofthe interior of said roller and having a perforate peripheral portionand an imporate peripheral portion forming a continuation of theperforate peripheral portion of said shell,

longitudinal seals extending along the outside of said air distributorshell, along opposite sides of the perforate peripheral portion thereof,for substantially the length thereof, and having sealing engagement withthe hollow interior of said roller,

circumferential sealing means sealing the ends of said shell to saidroller,

means admitting heated air to said shell through one end thereof,

and modulator valve means at opposite ends of said shell, to vary thevolume of air supplied to opposite end portions of said felt roller,

said modulator valve means comprising:

two 'wheels rotatably mounted at each end of said shell,

shrouds extending between said wheels for a portion of the circumferencethereof and positionable to shroud a portion of the perforate peripheralportion of said shell,

and means operable from the outside of said roller for independentlymoving said valve means at each end of said shell, at the selection ofthe operator of the dryer.

5. A felt roller comprising,

a roll shell having a cylindrical wall,

bearing means supporting said shell for free rotation about a horizontalaxis,

said wall having a plurality of uniformly spaced air passageways leadingtherethrough,

a cylindrical air distribution shell disposed within said roll shell andextending therealong for substantially the length thereof in inwardlyspaced relation with respect thereto,

said air distributor shell having air distribution passageways leadingtherethrough for a portion of the periphery thereof,

means admitting heated air to one end of said shell, circumferentialsealing means sealing opposite ends of said air distributor shell to theinterior of said roll shell,

and rotatable valve means within said air distributor shell at each endthereof and selectively operable from the outside of said shell to varythe flow of air thorugh the opposite end portions of said roll shell.

6. A felt roll in accordance with claim 5,

wherein the rotatable valve means Iat opposite ends of the airdistributor shell are in the form of wheels rotatably mounted Withinsaid shell,

wherein shrouds extend between said wheels,

and wherein the air pasageways open through the adjustably moving saidmodulator valves at opposite ends of the shell, independently of eachother, to vary the distribution of air through opposite ends of the rollshell.

7. A felt roll in accordance with claim 5,

wherein the roll shell is uniformly and longitudinally groovedthroughout the periphery thereof at spaced intervals,

and wherein the air passageways open through the bases of said groovesReferences Cited UNITED STATES PATENTS 849,141 4/1907 Ladd 34-1151,660,640 2/1928 Asten 34-111 1,718,573 6/1929 Millspaugh 34-1152,091,805 8/1937 Chuse 34-115 3,246,401 4/1966 Walser et al. 34--1153,262,218 7/ 1966 Cymbalisty 34-134 X FOREIGN PATENTS 645,065 7/ 1962Canada. 1,385,495 12/ 1964 France.

950,296 2/1964 Great Britain.

FREDERICK L. MATTESON, IR., Primary Examiner.

A. D. HERRMANN, Assistant Examiner.

('gffjy UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION Patent NoDated OCIOhCr l0,

lnventods) Robert A. Inzmc It is certified that; error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

rnlumn 7, line 26, correct spelling 0l' "impcrfomld',

Column 8, lim, 26, change "the nir pussngcwnys upcn through the" t0-c0axial operating means are provided fOr-f'.

SIGNED ANU SEALED NOV 4 1969 (SEAL) Attest:

Edward M.Fleher,1f. WILLIAM E. summa-3, JR.

cmissioner of Patents Attestmg Office!

1. IN A FELT ROLLER FOR PAPER MACHINE DRYERS COMPRISING: A CYLINDER ROLLSHELL MOUNTED FOR FREE ROTATION ABOUT A HORIZONTAL AXIS AND HAVING APLURALITY OF AIR PASSAGEWAYS LEADING THROUGH THE PERIPHERY THEREOF FROMTHE HOLLOW INTERIOR THEREOF FOR PASSING HEATED AIR THERETHROUGH, AHOLLOW NON-ROTATABLY CYLINDRICAL AIR DISTRIBUTOR SHELL SPACED RADIALLYINWARDLY OF THE INNER PERPIPHERY OF SAID ROLL SHELL AND EXTENDINGTHEREALONG AND HAVING A PERFORATE AREA HAVING AIR DISTRIBUTORPASSAGEWAYS LEADING THERETHROUGH FOR SUPPLYING HEATED AIR TO SAID AIRPASSAGEWAYS LEADING THROUGH THE PERIPHERY OF SAID ROLL SHELL,CIRCUMFERENTIALLY AND AXIALLY SPACED SEALING MEANS SEALING SAID AREA OFTHE INTERIOR OF SAID ROLL SHELL. AND MODULATOR VALVE MEANS ROTATABLYMOUNTED AT EACH END OF SAID DISTRIBUTOR SHELL FOR ADJUSTABLE MOVEMENTABOUT THE INNER PERIPHERY OF SAID DISTRIBUTOR SHELL, SAID MODULATORVALVE MEANS HAVING CIRCUMFERENTIALLY AND AXIALLY SPACED SEALS HAVINGSEALING ENGAGEMENT WITH THE INTERIOR OF SAID DISTRIBUTOR SHELL AND BEINGMOVABLE TO SEAL OFF THE OPPOSITE END PORTIONS OF THE PASSAGEWAYS LEADINGTHROUGH SAID DISTRIBUTOR SHELL AND TO VARY THE FLOW THROUGH SAIDPASSAGEWAYS, AND ADJUSTMENT MEANS CONNECTED WITH EACH MODULATOR VALVEMEANS FOR ADJUSTABLY MOVING SAID MODULATOR VALVE MEANS INDEPENDENTLY OFEACH OTHER.